1. Field
The present disclosure relates generally to aircraft and, in particular, to dimmable window systems in aircraft. Still more particularly, the present disclosure relates to a method and apparatus for increasing the reliability of dimmable window systems in aircraft.
2. Background
As part of the flying experience in aircraft, passengers may enjoy expansive views of the environment around the aircraft through windows in the passenger cabin. At other times, passengers may wish to reduce the light entering the passenger cabin.
For example, during takeoff, landing, or flight over landmarks, a passenger may wish to see these and other views around the aircraft through the passenger windows. When the passenger wishes to rest or when a movie is played, the passenger may desire to reduce the amount of light entering a window next to the passenger. As another example, the passenger may wish to reduce the amount of light entering a window to reduce heat inside the cabin caused by infrared radiation and ultraviolet radiation in the light.
The amount of light entering the cabin through the passenger window is controlled through a light blocking mechanism such as a window shade. Many aircraft employ mechanical shades that may be lifted up or down to either allow light to enter the cabin or block light from entering the cabin through a window.
With increasing frequency, mechanical shades are being replaced with dimmable windows. A dimmable window panel may be controlled by a passenger to change the amount of light entering passenger cabin.
A dimmable window panel typically changes the light transmission properties of the dimmable window panel when voltage or heat is applied to the window. For example, a dimmable window panel may be transparent, opaque, or may have some intermediate setting between being transparent and opaque. The dimmable window panel may also be referred to as smart glass.
The use of a dimmable window panel enables aircraft manufacturers to reduce weight on the airplane and, at the same time, greatly enhance passengers' flying experience by having the ability to control the amount of light entering into the cabin. For the operator of the aircraft, the maintenance cost is greatly reduced due to a reduction in moving parts. Further, the dimmable window panel may be installed in windows in the aircraft during upgrades or refurbishment of an aircraft. However, the maintenance for aircraft windows employing dimmable window panels may still be more than desired. Therefore, it would be desirable to have a method and apparatus that take into account at least some of the issues discussed above, as well as other possible issues.